Tornado - POST 中缺少“_xsrf”参数

Question

从下面的代码中可以看出，我有一个GET 用于注册，它将其工作委托给POST。

class RegistrationHandler(tornado.web.RequestHandler):
    def get(self):
        s = """
          <h1>Register</h1>
              <form method="post" action="/register">
                  <div>
                      <label>User</label>
                      <input name="user_name" value="test@test.com"/>
                  </div>
                  <div>
                      <label>password</label>
                      <input name="password" type="password"/>
                  </div>
                  <div>
                      <input type="submit" value="submit"/>
                  </div>
              </form>
        """
        self.write(s)

    @log_exception()
    def post(self):
        user_name = self.request.arguments['user_name']
        password = self.request.arguments['password']
        log.debug('Registering user with credentials %r' % (user_name, password))
        with sa_session() as db_session:
            User.register(user_name, password, db_session)

当我从网络浏览器访问该 URL 时，我会收到一个注册表单，提交后我会收到“403：禁止访问”。

控制台日志：

2012-10-15 11:27:42,482 - __main__ - DEBUG - Starting server on port 8080
2012-10-15 11:27:49,377 - root - INFO - 304 GET /register (127.0.0.1) 0.78ms
2012-10-15 11:27:53,143 - root - WARNING - 403 POST /register (127.0.0.1): '_xsrf' argument missing from POST
2012-10-15 11:27:53,144 - root - WARNING - 403 POST /register (127.0.0.1) 1.05ms

这个错误是什么意思，我该如何纠正？谢谢。

Answer 1

我想您在设置中启用了跨站点请求伪造 cookie （默认开启）。

Tornado's XSRF is here

要解决此问题，请在您的设置中将其关闭：

settings = {
    "xsrf_cookies": False,
}

注意：通常你不想关闭它，通常你会在这样的模板中生成 HTML：请注意添加 XSRF cookie 的 xsrf 位。

 <form method="post" action="/register">
     <input name="user_name" value="test@test.com"/>
     <input name="password" type="password"/>
     <input type="submit" value="submit"/>
{% raw xsrf_form_html() %}
 </form>

---编辑以下cmets--- 而不是：

  def get(self):
        loader = template.Loader("resources")
        page_contents = loader.load('register_page.html').generate()
        self.write(page_contents)

做：

  def get(self):
     self.render("../resources/register_page.html")

或更好：

  def get(self):
     self.render("register_page.html")

（并将其放在您的模板目录中）

Answer 2

同样的问题。 在深入研究代码后，我检查了执行该检查的 tornado 内置函数：

def check_xsrf_cookie(self):
    """Verifies that the ``_xsrf`` cookie matches the ``_xsrf`` argument.

    To prevent cross-site request forgery, we set an ``_xsrf``
    cookie and include the same value as a non-cookie
    field with all ``POST`` requests. If the two do not match, we
    reject the form submission as a potential forgery.

    The ``_xsrf`` value may be set as either a form field named ``_xsrf``
    or in a custom HTTP header named ``X-XSRFToken`` or ``X-CSRFToken``
    (the latter is accepted for compatibility with Django).

    See http://en.wikipedia.org/wiki/Cross-site_request_forgery

    Prior to release 1.1.1, this check was ignored if the HTTP header
    ``X-Requested-With: XMLHTTPRequest`` was present.  This exception
    has been shown to be insecure and has been removed.  For more
    information please see
    http://www.djangoproject.com/weblog/2011/feb/08/security/
    http://weblog.rubyonrails.org/2011/2/8/csrf-protection-bypass-in-ruby-on-rails

    .. versionchanged:: 3.2.2
       Added support for cookie version 2.  Both versions 1 and 2 are
       supported.
    """
    token = (self.get_argument("_xsrf", None) or
             self.request.headers.get("X-Xsrftoken") or
             self.request.headers.get("X-Csrftoken"))
    if not token:
        raise HTTPError(403, "'_xsrf' argument missing from POST")
    _, token, _ = self._decode_xsrf_token(token)
    _, expected_token, _ = self._get_raw_xsrf_token()
    if not token:
        raise HTTPError(403, "'_xsrf' argument has invalid format")
    if not _time_independent_equals(utf8(token), utf8(expected_token)):
        raise HTTPError(403, "XSRF cookie does not match POST argument")

你可以读到方法定义：

_xsrf 值可以设置为名为 _xsrf 的表单字段 或在名为 X-XSRFToken 或 X-CSRFToken 的自定义 HTTP 标头中

因此我尝试设置一个名为 X-CSRFToken 的 HTTP 标头。以下是ajax定义：

$.ajax({
    url: this.my_url,
    type: 'POST',
    data: JSON.stringify(body),
    beforeSend: function(xhr) {
            xhr.setRequestHeader('X-CSRFToken', getCookie('_xsrf'));},
});

最后，我们需要定义函数getCookie，它负责检索正确的CSRF-token。这个函数的定义直接取自TornadoCSRF documentation：

function getCookie(name) {
    var r = document.cookie.match("\\b" + name + "=([^;]*)\\b");
    return r ? r[1] : undefined;
}

Answer 3

有冲突： 您如何制作 get 并以您输入的形式 method="post" ？这就是为什么会有error 403

如果您使用get，那么您将不需要xsrf 保护。否则，您将其添加到表单声明之后

<form method="post" action="/register">
{% raw xsrf_form_html() %} # the 'raw' word is to force escape to be desactivated (it is by default activated)

所以 xsrf 你会在渲染的 html 中发现它是一个隐藏标签。